Influence of blast exposure on cognitive functioning in combat veterans.

OBJECTIVE: We evaluated the contribution of blast-pressure severity to cognitive functioning beyond posttraumatic stress disorder (PTSD) severity and traumatic brain injury (TBI).
METHOD: Post-9/11 veterans (N = 254, 86.22% male) completed the Wechsler Adult Intelligence Scale (WAIS-IV) and Trail Making Test (TMT). The Clinician-Administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI, and the Salisbury Blast Interview evaluated PTSD diagnosis/severity, deployment TBI history/severity, and blast-exposure history/severity, respectively.
RESULTS: Veterans with mild deployment TBI had overall significantly lower T scores on the WAIS-IV Verbal Comprehension Index (d = .13), Working Memory Index (d = .30), and Processing Speed Index (d = .25); the Trail Making Test A (TMT-A; d = .50); and the Trail Making Test B (TMT-B; d = .37). Mild deployment TBI was significantly associated with TMT-A (ΔR² = .05, p < .001) and TMT-B (ΔR² = .03, p = .001) performance. Blast-pressure severity moderated the association between mild deployment TBI and TMT-A (ΔR² = .02, p = .039, B = -2.01).
CONCLUSION: Blast-pressure severity exacerbated the effects of mild TBI on a simple attention task, such that participants with TBI had gradual decrements in attention as blast severity increased. Veterans who incur a TBI and are exposed to blasts during deployment may experience persisting difficulties with cognitive functioning as a result of alterations in basic attention abilities. (PsycInfo Database Record (c) 2020 APA, all rights reserved).